1. Field of the Invention
The present invention relates to a controlling apparatus for gate driving signal, especially to a controlling apparatus for gate driving signal with simple circuit layout and enhanced terminal utilization efficiency.
2. Description of Prior Art
Industrial safety and equipment safety become serious concern as the advance of technology and demand on life quality. For example, performance levels (PL) and safety integrity levels (SIL) are two popular industrial standards for safety of electronic control system. The two standards have different regulation to provide corresponding protection. PL standard is first enacted in 1990s, which is part of EN954-1 and supports EU machinery Directive
The degree of malfunction in a machine or system can be classified into Category B, 1, 2, 3 and 4 in view of endurance for malfunction and performance under malfunction condition. More particularly, Category 3 safety standard provides enhanced safety by redundancy and dual-channel skill. Moreover, the malfunction can also be detected. For example, Rockwell has developed a Safe-Off protection scheme with redundancy approach.
FIG. 1 shows the block diagram of a prior art apparatus 10 for controlling gate driving signal, which mainly comprises a processor 100, a first gate-controlling integrated circuit (IC) 120, and a second gate-controlling IC 140. The processor 100, the first gate-controlling IC 120, and the second gate-controlling IC 140 are in serial connection to convey a gate driving signal. The gate driving signal is sent to a photo coupler 160 to control a gate (not shown) of a power unit (not labeled), wherein the power unit is an IGBT inverter.
The first gate-controlling IC 120 comprises an output end electrically connected to an isolation multiple input unit 180 to receive external signal. The isolation multiple input unit comprises an input end electrically connected to an enable jumper 182 for receiving an external enable signal. The second gate-controlling IC 140 is electrically connected to an optional safe relay 150 in order to receive a control signal from the safe relay 150. The processor 100 receives four control signal SA, SB, SC and SD. The control signal SA detects whether the safe relay 150 is correctly installed. The control signal SB detects whether the safe relay 150 has normal operation. The control signal SC detects whether the first gate-controlling IC 120 has normal operation. The control signal SD detects whether the second gate-controlling IC 140 has normal operation. The provision of the enable jumper 182 and the safe relay 150 enables user to disable the gate driving signal, thus preventing the malfunction due to single circuit.
However, in above-mentioned apparatus 10 for controlling gate driving signal, the cost is high and larger area is occupied in PCB because two gate-controlling ICs are required. Moreover, the isolation multiple input unit 180 has one input end connected tot the enable jumper 182, the input end is waste when safety is not a concern.